Means for securing printing plates to their bases



Sept. 3, 1946. 2,406,883

MEANS FOR SECURING PRINTING PLATES To THEIR BASES HQ J. LUEHRS FiledFeb; 17, 1943 IN V EN TOR.

Patented Sept. 3, 1946 MEANS FOR SECURING PRINTING PLATES TO THEIR BASESHans J. Luehrs, Westerly, R. I., assignor to C. B.

Cottrell &

Sons Company, Westerly, R. 1., a corporation of Delaware ApplicationFebruary 17, 1943, Serial No. 476,198

In the usual means for and method of securing printing plates to theirbases, such, for instance, as plate cylinders, it has been customary tosecure the plates to their bases under compression by the use of plateclamps which overlapped, in the past, beveled marginal edges of theplates. These clamps served to force the plates inwardly at theirmarginal edges and thus prevented their firm and close contact withtheir bases throughout the entire back surfaces of the plates.

Furthermore, the interposition of the usual plate clamps between thebeveled edges of adjacent plates also prevented their close positioningon their bases,thereby resulting in a considerable loss of paper as Wellas average production.

Furthermore, the plates, because of this compression, were liable tobecome loosened and displaced and thus caused much damage, especiallywhen the plates were secured to plate cylinders designed to rotate atthe high speeds now required for increased production; the centrifugalaction causing undue stresses on the plates.

The object of my invention is to firmly and snugly secure the plates totheir basesby causing the jaws of the adjustable plate register hooks toengage the backs of the plates adjacent their marginal edges and exert apull on the plates at their margins in securing the platesunderlengthwise and crosswise tension to their bases.

This arrangement also permitted the plates to be. positioned on theirbase much closer together, both by the elimination of their bevelededges and by the removal of the hook jaws from between the plates topositions underneath the plates.

A further object is to secure the plates to their grooved bases byproviding grooves alongv the backs of the plates adjacent their marginaledges and providing register hooks which'are adjustable along their basegrooves, with their plate engaging jaws arranged to enter the said plategrooves; the coacting sides of the grooves and jaws being shaped tocause the hooks to exert tension on the plates, toward the base, bothlengthwise and crosswise of the plates, when securing them to theirbases. i

A further object is to provide a novel arrangement of the severalelements of the plate register hooks whereby the instrument for manuallyadjusting the plates along the base grooves may be applied to the hookpropelling gears between the squared edges of the plates instead ofapplying the said instrument to thehook propelling gears through theplate engaging jaws of the hook.

6 Claims. (01. 101--388) A practical and novel means for carrying out myinvention is represented in the accompanying drawing in which Fig. 1represents a detail plan view showing the adjacent corners of fourprinting plates secured to their plate cylinder;

Fig. 2 represents a detail section taken in the plane of the line IIIIof Fig. l;

Fig. 3 represents a detail section taken in the plane of the lineIII--III of Fig. 1;

Fig. 4 represents a top plan view of the plate register hook, on anenlarged scale, the plate engaging jaw and double winged locks beingshown in their plate securing positions;

Fig. 5 represents an inside View of the plate register hook with one ofits complementary body members removed;

Fig. 6 represents an inside View of the removed complementary bodymember of the hook;

Fig. 7 represents a transverse section through the register hook, takenin the plane of the line VII-VII of Fig. 4;

Fig. 8 represents a transverse section, taken in the plane of the lineVIII-VIII of Fig. 4-;

Fig. 9 represents a transverse section taken in the plane of the lineIXIX of Fig. r;

Fig. 10 represents a detail back view of one of the printing plates onthe same scale as that shown in Figs. 1, 2 and 3; and

Fig. 11 represents a side View of an instrument ,which might be used foreither propelling the plate register hook or for operating the seconddoublewinged lock.

The base to which the printing plates are to be secured is herein shownas a plate cylinder I having spaced helical grooves 2 provided withracks 3 along their bottom walls and with overhanging ledges 4, 4along'their side walls, as is usual. The curved printing plates 5 areeach shown as having four squared marginal edges 6 instead of the usualbeveled edges, thus permitting the plates to be positioned in closeproximity to one another on their cylinder. plates 5 also have grooves 1extending along their backs adjacent their squared edges 6, whichgrooves are arranged to receivethe jaws of the plate register hooksto beimmediately described.

The elongated body of the register hook is shown as dividedlongitudinally and vertically intotwoc'omplementary members 8, 9removably fastened together by crossscrews Hi. This divided body isshaped to permit its ready insertion into and removal from its cylindergroove 2 at any desired point along; the same,.when: the

These I 3 two locks carried by the hook are housed within the body intheir retracted positions.

The plate engaging jaw II, the double winged lock I2 and theirconnecting neck I3 are formed integral, to cause the jaw II, as it isturned, to swing the double winged lock I2 to its extended and retractedpositions. The neck I3 of the combined jaw and lock is journaled in adivided opening I4 which extends upwardly through the top of the hookbody and also downwardly into a divided recess I5 opening through thesides of the body and shaped to fit the double winged lock A seconddouble winged lock I6 has a hollow central bore which is journaled in adivided opening I8 extending upwardly through the top of the body andalso downwardly into a divided recess l9 opening through the sides ofthe body, and shaped to fit said second double winged lock I6. This lockI6 may be turned into its extended and retracted positions by theapplication of a suitable instrument, such as a key having a shank 2I ofnon-circular cross section, to fit the non-circular bore 22 through saidlock IS.

The means for propelling each of the plate register hooks along itscylinder groove 2 to cause the undercut inclined side 23 of the jaw I Ito engage the undercut inclined wall 24 of the selected plate glooVe I,is shown as comprising the following elements: a horizontally disposedrack engaging gear 25 is located in a suitably shaped divided recess 28which opens through the bottom of the body to permit the gear to engagethe cylinder rack 3. The shaft extensions 21, 28 of the gear 25 arejournaled in openings 29, 30 in the body members 8, 9. The hollowvertically disposed worm 3| which meshes with the rack engaging gear 25is located in a suitably shaped divided recess 32 in the body and itsupper and lower shaft extensions 33, 34 are journaled in dividedopenings 35, 3G in the body.

This hollow worm 3! is located in axial alinement with the hollow secondlook It and the non-circular bore 3'8 of the worm is smaller in diameterthan the non-circular bore 22 of the second lock I5 for the fittedreception of the second non-circular shank 38 of the key 20, which shankmay be inserted freely through said second lock bore 22.

Means such as spring pressed balls 39, 40 located in recesses M, 42 inone of the members of the body, may be employed for yieldingly holdingthe first and second locks I2 and I6 in their extended and retractedpositions.

In operation: the plate register hooks are positioned along the cylindergrooves 2 in proper positions to cause their plate engaging jaws I I toenter their selected plate grooves 1. The second double winged lock I6may then be brought into its extended position in engagement with theundersides of the ledges 4, 4 by the insertion and operation of theshank 2i of the key 2|]. The shank 38 of the hook propelling key 20 maythen be inserted between the adjacent squared edges 8 of the plates 5and freely through the bore 22 of the second look I6 of each of theplate register hooks, into'the bore 31 of the worm 3 I. By turning thiskey the hook will be propelled a short distance along the cylindergroove 2 to bring the undercut inclined wall 23 of the jaw I I intocontact with its coacting undercut inclined outer wall 24 of the plategroove 1 in which the hook is located. The further turning of the keywill cause the jaw to pull the plate under tension, both lengthwise andcrosswise, snugly and firmly onto its cylinder I and also cause thefirst double winged lock I2 to snugly engage the undersides of thecylinder groove ledges 4, 4.

It will be noted that by making the combined jaw and lock imperforate,the elements will be much stronger and consequently more efficient,especially where the hooks are subjected to the great strain due to thepull on the plates to tension them and to the stresses caused by thecentrifugal action of the cylinder under the high speeds now requiredfor increased production.

It will also be seen that the propelling gears 25 and 3| cannot bemanipulated by an instrument inserted through the combined jaw and lookas the same will be located underneath the plate when the plate registerhook is positioned to secure the plate to its cylinder.

It will also be observed that the hook propelling means is operated byan instrument inserted through the second look at a point spaced alongthe hook body from the combined jaw and look.

It will also be seen that by providing larger and smaller boresrespectively for the second look and the worm, the second lock may beoperated independently of the propelling means after the hook has beenbrought into its position to snugly draw the plate under tension to itscylinder.

It will be understood that by the term base as used in the claims hereinI wishto include a base having either a fiat surface for use with flatprinting plates; or a base having a curved surface, as a plate cylinderfor use with curved printing plates; the plate register hooks beingessentially the same in their construction and operation in eachinstance.

The elements shown and described but not claimed herein form the subjectmatter of my copending application filed of even date herewith, itsserial number being 476,199.

What I claim is:

1. A base having spaced grooves along its surface, a printing platehaving intersecting grooves along its back adjacent all of its marginaledges, plate register hooks engaging said base and plate grooves, andmeans for propelling the hooks along the base groove in directions tosecure the plate to the base under tension comprising propelling gearswithin said hooks and a suitable removable instrument insertable intothe hooks for operative engagement with said propelling gears.

2. A cylinder having spaced spiral grooves along its surface, a curvedprinting plate having intersecting grooves along its back adjacent itsstraight and curved marginal edges, plate register hooks engaging saidcylinder and plate grooves, and means for propelling the hooks along thecylinder grooves in directions to secure the plate to the cylinder undertension comprising propelling gears within said hooks and a suitableremovable instrument insertable into the hooks for operative engagementwith said propelling gears.

3. A base having spaced grooves along its surface, a printing platehaving intersecting grooves along its back adjacent all of its marginaledges, and plate register hooks engaging said base and plate grooves forsecuring the plate to the base under tension, each hook comprising abody having journaled therein an axially imper'forate combined jaw andlock and hook propelling gears, said body and one of said gears havingaxially alined holes spaced from the said coming ,journaled therein anaxially imperforate bined jaw and lock for the insertion of a suitablecombined jaw and lock, a second look and hook instrument into operativeengagement with said propelling gears, said body, second lock and onegears. of said gears having axially alined holes spaced 4. A cylinderhaving spaced spiral grooves 5 from the said combined jaw and lock forthe along its surface, a curved printing plate having insertion of asuitable instrument into independintersecting grooves along its backadjacent its ent operative engagement with said second lock straight andcurved marginal edges, and plate and gears. register hooks engaging saidcylinder and plate 6. Acylinder having spaced spiral grooves alonggrooves for securing the plate to the cylinder 10 its surface, a curvedprinting plate having interunder tension, each hook comprising a bodysecting grooves along its back adjacent its straight having journaledtherein an axially imperforate curved marginal edges, and plate registerhooks combined jaw and lock and hook propelling engaging said cylinderand plate grooves for segears, said body and one of said gears havingcuring the plate to the cylinder under tension, axially alined holesspaced from the said com- 15 each hook comprising a body havingjournaled bined jaw and lock for the insertion of a suitt re n an axiamp f ate c m n d jaw and able instrument into operative engagement withlook, a second look and hook propelling gears, said gears. said body,second look and one of said gears hav- 5. A base having spaced groovesalong its suring axially alined holes spaced from the said face, aprinting plate having intersecting grooves 20 combined jaw and lock forthe insertion of a suitalong its back adjacent all of'its marginaledges, able instrument into independent operative enand plate registerhooks engaging said base and gagement with said second lock and gears.plate grooves for securing the plate to the base under tension, eachhook comprising a bod haw HANS J. LUEHRS.

